CN201312290Y - SF458 saw filter for railway communication - Google Patents
SF458 saw filter for railway communication Download PDFInfo
- Publication number
- CN201312290Y CN201312290Y CNU200820233765XU CN200820233765U CN201312290Y CN 201312290 Y CN201312290 Y CN 201312290Y CN U200820233765X U CNU200820233765X U CN U200820233765XU CN 200820233765 U CN200820233765 U CN 200820233765U CN 201312290 Y CN201312290 Y CN 201312290Y
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- transducer
- filter
- acoustic wave
- surface acoustic
- wave filter
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Abstract
The utility model discloses an SF458 saw filter for railway communication, comprising a 36-degree lithium tantalate substrate provided with an image impedance filter IIDT. The image impedance filter IIDT comprises an upper transducer and a lower transducer, wherein the upper transducer and the lower transducer are coupled in a mirror image way up and down. The SF458 saw filter for railway communication with center frequency of 457.45 to 458.55 MHz, -2dB bandwidth of 2.5 to 2.6 KHz and -40dB bandwidth of 5.6 to 5.8 MHz is characterized by low loss, high rectangular degree, narrow band and high band external inhibition, and can satisfy application requirements of radio station and the like.
Description
Technical field
The utility model relates to a kind of Surface Acoustic Wave Filter, relates in particular to a kind of SF458 sections road communication Surface Acoustic Wave Filter.
Background technology
When the crystal with piezoelectric effect is subjected to mechanism, the phenomenon of the electric field that is directly proportional with pressure will be produced; Crystal with piezoelectric effect when being subjected to action of electric signals, also can producing elastic deformation and sends mechanical wave (sound wave), can transfer the signal of telecommunication to acoustical signal.Because this sound wave is only propagated at plane of crystal, so be called surface acoustic wave.
Surface Acoustic Wave Filter (SAWF) has that volume is little, in light weight, dependable performance, do not need the complicated advantage of adjusting, and is that signal receives the Primary Component of handling in the radio communication.
There is following shortcoming at least in SAW (Surface Acoustic Wave) device of the prior art: the loss height of filter.
Summary of the invention
The purpose of this utility model provides a kind of low SF458 sections road communication Surface Acoustic Wave Filter of loss of filter.
The purpose of this utility model is achieved through the following technical solutions:
SF458 sections of the present utility model road communication Surface Acoustic Wave Filter, comprise substrate, described substrate is provided with the image impedance filter, and described image impedance filter comprises transducer, following transducer, describedly goes up transducer and the upper and lower mirror-image arrangement of following transducer and intercouples.
The technical scheme that provides by above-mentioned the utility model as can be seen, communication Surface Acoustic Wave Filter in SF458 sections described in the utility model road because substrate is provided with the image impedance filter, can reduce two-way loss, makes the loss reduction of whole filter.
Description of drawings
Fig. 1 is the structure principle chart of the utility model SF458 sections road communication with Surface Acoustic Wave Filter;
Fig. 2 is the encapsulating structure schematic diagram of the utility model SF458 sections road communication with Surface Acoustic Wave Filter.
Embodiment
SF458 sections of the present utility model road communication Surface Acoustic Wave Filter, its preferable embodiment as shown in Figure 1, comprise substrate 8, substrate 8 is provided with image impedance filter IIDT, the image impedance filter comprises transducer 9, following transducer 10, and last transducer 9 and following transducer 10 can upper and lower mirror-image arrangement and intercoupled.
Transducer 11 in the middle of last transducer 9 and following transducer 10 can comprise respectively, middle transducer 11 is the withdraw-weighted unit.Promptly middle transducer 11 is carried out withdraw-weighted and handle, make the outer height that suppresses of band, loss is low, is fit to relative bandwidth narrow (about 2%), the device that loss is low.
As shown in Figure 2, the utility model comprises encapsulating structure, and encapsulating structure is provided with input pin 3 and output pin 4, can also be provided with a plurality of grounding pins 1,2,5,6.
Referring to Fig. 1, input pin 3 can be connected with following transducer 10 with last transducer 9 respectively with output pin 4; Also can exchange, input pin 3 is connected with last transducer 9 with following transducer 10 respectively with output pin 4.Last transducer 9 also is connected with at least one grounding pin respectively with following transducer 10.
Surface Acoustic Wave Filter is used in the communication of SF458 sections of the present utility model road, can be the filter of 457.45～458.55MHz for centre frequency; Also can for-the 2dB bandwidth is the filter of 2.5～2.6MHz; Also can for-the 40dB bandwidth is the filter of 5.6～5.8MHz.Low-loss, high rectangle degree, arrowband (about 2%), the outer height that suppresses of band can satisfy the requirement of railway communication or other applications.
The electric parameter of a specific embodiment, as shown in table 1:
The electric parameter of table 1, specific embodiment
The above; it only is the preferable embodiment of the utility model; but protection range of the present utility model is not limited thereto; anyly be familiar with those skilled in the art in the technical scope that the utility model discloses; the variation that can expect easily or replacement all should be encompassed within the protection range of the present utility model.
Claims (9)
1, a kind of SF458 sections road communication Surface Acoustic Wave Filter, comprise substrate, it is characterized in that described substrate is provided with the image impedance filter, described image impedance filter comprises transducer, following transducer, describedly goes up transducer and the upper and lower mirror-image arrangement of following transducer and intercouples.
2, Surface Acoustic Wave Filter is used in SF458 sections road communication according to claim 1, it is characterized in that, the described transducer of going up comprises middle transducer respectively with following transducer, and described middle transducer is the withdraw-weighted unit.
3, SF225M2 type Surface Acoustic Wave Filter according to claim 1 is characterized in that, described substrate is a lithium tantanate substrate.
4, SF225M2 type Surface Acoustic Wave Filter according to claim 3 is characterized in that, described lithium tantalate is 36 ° of lithium tantalates.
5, use Surface Acoustic Wave Filter according to claim 1, the communication of 2 or 3 described SF458 sections roads, it is characterized in that this filter is that centre frequency is the filter of 457.45～458.55MHz.
6, use Surface Acoustic Wave Filter according to the communication of claim 1,2 or 3 described SF458 sections roads, it is characterized in that, this filter is-the 2dB bandwidth is the filter of 2.5～2.6MHz.
7, use Surface Acoustic Wave Filter according to the communication of claim 1,2 or 3 described SF458 sections roads, it is characterized in that, this filter is-the 40dB bandwidth is the filter of 5.6～5.8MHz.
8, according to claim 1,2 or 3 described SF458 sections roads communication Surface Acoustic Wave Filter, it is characterized in that, comprise encapsulating structure, described encapsulating structure is provided with input pin and output pin, and described input pin is connected with following transducer with the described transducer of going up respectively with output pin; Perhaps, described input pin is connected with last transducer with described transducer down respectively with output pin.
9, Surface Acoustic Wave Filter is used in SF458 sections road communication according to claim 8, it is characterized in that described encapsulating structure is provided with a plurality of grounding pins, and the described transducer of going up is connected with at least one grounding pin respectively with following transducer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU200820233765XU CN201312290Y (en) | 2008-12-23 | 2008-12-23 | SF458 saw filter for railway communication |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU200820233765XU CN201312290Y (en) | 2008-12-23 | 2008-12-23 | SF458 saw filter for railway communication |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201312290Y true CN201312290Y (en) | 2009-09-16 |
Family
ID=41109545
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU200820233765XU Expired - Lifetime CN201312290Y (en) | 2008-12-23 | 2008-12-23 | SF458 saw filter for railway communication |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201312290Y (en) |
-
2008
- 2008-12-23 CN CNU200820233765XU patent/CN201312290Y/en not_active Expired - Lifetime
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee |
Owner name: BEIJING ZHONGXUN SIFANG SCIENCE TECHOLOGY CO., L Free format text: FORMER NAME: BEIJING ZXSF SCIENCE + TECHNOLOGY CO., LTD. |
|
| CP03 | Change of name, title or address |
Address after: 100193, room 2, building 2245, incubator of Beijing Zhongguancun Software Park, Haidian District, Beijing, Northeast China Patentee after: Beijing Zhongxun Sifang Science and Technology Co., Ltd. Address before: 100094 Beijing City, northeast of Haidian District Road, No. 37 Patentee before: Beijing ZXSF Science & Technology Co., Ltd. |
|
| PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of utility model: SF458 saw filter for railway communication Effective date of registration: 20101213 Granted publication date: 20090916 Pledgee: Bank of Communications Ltd Beijing Zhongguancun Park sub branch Pledgor: Beijing Zhongxun Sifang Science and Technology Co., Ltd. Registration number: 2010990001004 |
|
| PC01 | Cancellation of the registration of the contract for pledge of patent right |
Date of cancellation: 20111103 Granted publication date: 20090916 Pledgee: Bank of Communications Ltd Beijing Zhongguancun Park sub branch Pledgor: Beijing Zhongxun Sifang Science and Technology Co., Ltd. Registration number: 2010990001004 |
|
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20090916 |